Once a brushtail possum is excluded from your roof, it has to go somewhere. Victorian rules say a trapped possum must be released within 50 metres of where it was caught, so it will stay in your garden or your neighbour's. A possum box gives it a safe nest close by, which makes it less determined to break back into the roof. This page explains why, and how boxes are sized and placed.
Ballarat Possum Removal is a referral service. We do not build or install possum boxes. With your consent, we pass your enquiry to an independent local business that supplies and installs them, usually as part of a removal and proofing job.
Why a box helps
Brushtail possums live in small home ranges and defend them. Relocation is prohibited in Victoria, and DEECA cites research showing that most relocated possums die soon after release. Lawful options are exclusion and same-property release. Both leave the possum nearby. Without a good shelter it will look hard for a way back in. A box in a tree gives it a dry, safe den, which is what it was looking for in your roof in the first place.
A box is not a fix on its own. It works with proofing, not instead of it. If the roof is not sealed, the possum will simply choose the roof again.
Size and design
Guidance from state wildlife agencies is broadly consistent. For a brushtail:
- Material: untreated solid timber or exterior plywood, not chipboard, which falls apart when wet.
- Size: roughly 300 mm square at the base and 450 to 500 mm high, which suits a single adult brushtail.
- Entrance: a hole about 110 to 120 mm wide near the top of the front or side, under an overhanging lid.
- Roof: sloped and sealed, with a strip of metal or rubber along the hinge so rain cannot get in.
- Drainage: a few small holes in the floor.
- Bedding: some dry leaves or untreated wood shavings.
Placement in a Ballarat garden
- Mount it at least 4 metres above the ground, out of reach of dogs, cats and foxes.
- Fix it to a sturdy tree with straps or bolts that allow for growth, not a nail driven into the trunk.
- Face the entrance away from prevailing weather. In Ballarat that usually means away from the cold, wet westerly and south-westerly winds.
- Place it in shade, so it does not overheat in summer.
- Keep it away from the house, so that it does not become a stepping stone back onto the roof.
Some owners put a little of the old nest material, or a piece of fruit, in the box to encourage the possum to use it. Feeding possums regularly is discouraged, because it brings more of them.
Maintenance
Check the box once or twice a year from the ground. Starlings, Indian mynas, bees and European wasps sometimes move in. If bees or wasps are present, get a professional to deal with them. Replace the box when the timber starts to rot.
Ringtails and other residents
Ringtail possums rarely nest in roofs and build their own leafy nests in dense shrubs. A brushtail box is not suited to them. Do not trap ringtails: in Victoria, it is illegal without a permit.
Building or buying a box
Possum boxes are sold by hardware stores, wildlife groups and some pest businesses, and many owners build their own from plans published by state environment departments. A bought box is quicker. A home-built one can be made to suit a particular tree. Either way, check the entrance size, that the lid sheds water, and that the box is solid enough to last several Ballarat winters. A thin or poorly sealed box gets damp and cold, and an evicted possum will soon go looking for a warmer roof.
If you have more than one brushtail around the house, more than one box may be needed, because adult brushtails usually den alone. Spread boxes across different trees rather than clustering them. If you have no suitable tree, a box can be fixed to a tall, sturdy pole or a fence post extension, as long as it is well clear of the roofline and out of reach of dogs. Ask the installer what will work on your block.
How a box fits into a removal job
In a typical job the box goes up on or before the day the possum is excluded or released, so it has somewhere to go that night. The installer then seals the roof, and the box gives the possum a reason not to keep testing the repairs. Ask whether box supply and installation are included in the quote or priced separately, and what height and tree the installer proposes.
Frequently asked questions
Do possum boxes actually work?
They help when combined with proper roof proofing. On their own they do not stop a possum from returning to a roof it can still get into.
Where should I put a possum box?
At least 4 metres up in a sturdy tree, sheltered from wind and afternoon sun, and away from the house. In Ballarat, face the entrance away from the prevailing westerly weather.
What size possum box does a brushtail need?
About 300 mm square and 450 to 500 mm high, with an entrance of roughly 110 to 120 mm. Use solid timber or exterior plywood, not chipboard.
Can I move the possum and its box to a park or bushland?
No. Relocation is prohibited in Victoria. A trapped brushtail must be released on the same property within 50 metres of capture, so the box belongs in your garden.
Should I feed the possum to get it into the box?
A small piece of fruit at first can encourage a possum to explore a new box. Ongoing feeding is discouraged, because it draws more possums and harms their health.
Next step
Tell us your suburb and whether you also need removal and proofing. With your consent, we pass your details to one independent Ballarat-area business. See how it works or make an enquiry.